How to permanently delete data on Samsung Galaxy?

1. How do I delete all data from the SIM card of a Samsung Propel a767?
I recently got a used Samsung Propel a767 and things such as the text messages of the previous owner are stored on the phone. Is there a way to delete all data on the SIM card? - Ray

2. How to wipe deleted data on my Samsung Galaxy S4 permanently?
With Samsung Galaxy S5 on selling,i want to resell my Samsung Galaxy S4 to others.So,i must need to erase all my data including contacts,messages,photos,videos,and more on my old Samsung Galaxy S4 ,but how can i wipe all data &deleted data on my Samsung Galaxy S4 permanently? - Jisson

Are you ready to resell, recycle or donate your old Samsung? Do you want to delete all of your data before dealing with your device? Many users of ideas have the same view with you, however, simple deletion or restore your Samsung to factory settings doesn't mean that you can permanent delete all personal data like contacts, messages, call logs, photos, videos, history, Apps and more from your Samsung devices, when your wipe your data via these ways, in fact, some of your data can still being recovered by using some data recovery tool.

If you want to permanently erase all data on Samsung, need a professional tool - Android Data Eraser to help us, recommend the Mobile Tranfer, which allows you to backup your Android to PC, and erase all data or the deleted data on Android phone, tablet, or other devices with a click. No matter you are the user of Samsung, HTC, LG, Motolora, Sony, HuaWei, etc., you can easily delete all data like photos, videos, contacts, text messages, and other personal information from your Android.

You can free download a trial version here and have a try.
(Notes: The Mac version is only allows to transfer data between Android and iOS devices at present.)

Permanently Delete data on Samsung Galaxy

Step 1. Download & install the Android Data Eraser
Download and intall the Android Data Eraser, then run it, you will get the main screenshot as follow.

Step 2. Do backup your Samsung (if you need)
Before you get started, please backup your Samsung data first. All data on your Samsung phone will be totally wiped and can't be recovered. So you would betther to back up the data. Connect your Samsung phone, then Select the "Back up your Phone" Mode to copy Samsung data to your computer.